CHEMICAL BURNS - EPIDEMIOLOGY

Vaglenova E.

Burn and Plastic Surgery Centre, Pirogov Emergency Medical Institute, Sofia, Bulgaria

SUMMARY. This survey considers the 5-year period 1991-1995, during which the total number of burn patients admitted to our clinic was 1548. Forty-nine (3.2%) presented chemical burns (38 male/11 female; mean age, 41.4 yr; age range, 14 to 80 yr). The commonest cause of chemical burns was some form of acid. The home was the most frequent site of chemical burn incidents (73.5% of all such cases), the main reasons being criminal acts or negligence. Burn extent ranged from I to 95% TBSA, with a predominance of injuries in less than 10% TBSA. Thirty-six patients (73.5%) presented deep partial-thickness and full-thickness skin loss. The head, face, and neck were affected in 31.8% of the patients, the lower limbs in 30.8%, the upper limbs in 19.6%, and the trunk in 17.8%. Patient mortality in this series was 4. 1 %.

Considering Bulgaria's limited surface area, chemical industries are well represented. However, our research indicates that chemical burns are quite rare, constituting only 3.2% of all burns treated in our centre in the 5-year period 1991-1995.
In this paper we analyse cases of chemical burns admitted to our centre during this period.

Between 1991 and 1995, 1548 adult burn patients were treated in our clinic, of whom 49 (3.2%) presented burns due to chemical agents (Fig. 1).

The annual percentage varied between 1.6 and 5.2% (Table 1).

Fig. 1 - Frequency of chemical burns among 1548 adult patients

Epidemiological analysis

The age of the patients ranged between 14 and 80 yr (Fig. 2). The accidents occurred most frequently to patients of active working age (20-60 yr). The mean age was 41.4 years, varying during the 5-year period from a minimum of 33.4 yr in 1992 to a maximum of 56.5 yr in 1994 (Fig. 3) The male to female ratio was 38:11 (77.6%:22.4%) (Fig. 4). In 36 cases (73.5%) the burns were suffered at home as a result of carelessness or criminal action (Fig. 5). Accidents at work constituted 13 cases (26.5%).

Fig. 2 - Distribution by age and sex. Fig. 3 - Distribution by mean age. Fig. 4 - Distribution by sex. Fig. 5 - Distribution by place of accident.

With regard to the cause of the burns, acids played a primary role (42.8% of cases). Sulphuric and nitric acids were most frequently involved. Burns caused by bases represent 30.6% of the cases, most frequently caustic soda (sodium hydroxide). The agent was not definitely established in 12.2% of the patients (Fig. 6).
Burned total body surface area (TBSA) varied from I to 95% (Fig. 7). In the great majority of cases (77.5%) the burns affected less than 10% TBSA. The mean burn extent was 8. 1 % TBSA.

Fig. 6 - Distribution by cause of burn Fig. 7 - Distribution by burn size (T13SA).

Thirty-six patients (73.5%) presented deep partial-thickness and full-thickness skin loss, treated by surgery. The remaining thirteen patients (26.5%) had superficial burns, and epithelialization occurred spontaneously (Fig. 8).
The body area most frequently affected was the head and neck (31.8%). This is typical of criminal acts and is comparatively rare in industrial accidents. The most frequent localizations were the lower limbs (30.8%), the upper limbs (19.6%), and the trunk (17.8%) (Fig. 9).

Fig. 8 - Distribution by burn depth. Fig. 9 - Distribution by body parts affected.

If we consider the localization of the burns and the surgical operations performed on the sites (Fig. 10) it can be seen that the highest percentage of operations was for burns in the lower limbs (72.7%), followed by the head and neck (58.8%) and the upper limbs (57. 1 %).

Fig. 10 - Comparison of localization of burns and sites subjected to surgery.

The mean hospital stay was 27.1 days. Only eight patients (16.3%) were admitted to the centre in the immediate post-trauma phase. The mortality rate in the series was 4. 1 %.

Chemical burn patients treated in our centre in the 5year period 1991-95 constituted 3.2% of all patients admitted (the corresponding figure in 1968 was 10.0%). Other authors` give higher percentages for chemical burns (4.P 13.3%), although we are aware that the data are not absolutely comparable.
In spite of the widespread presence of the chemical industry in our country it is remarkable that industrial chemical burns constitute only thirteen of all the chemical burns treated (26.5%). This contrasts with other reports in which the majority of accidents were of industrial origin. 1-3,6
Among our cases the most frequent accidents (63.7%) involved persons of active working age (20-60 yr), predominantly male (77.5%). The leading causes of the chemical burns were sulphuric acid, nitric acid, and caustic soda (sodium hydroxide). There were no burns due to Lysol, which is no longer used in our hospitals .7 As we have said, the mean burned T13SA was 8.1%, i.e. the majority of burns involved less than 10% T13SA. There was a predominance of burns (73.5%) involving deep partial-thickness and full-thickness skin loss which necessitated operative treatment. The operations most frequently concerned the lower limbs, despite the high incidence of burns localized in the head and neck (31.8%). This can be explained by the prolonged contact of the chemical agent in the lower part of the body, with more serious effects. Another reason is that when the burn is in the face or the upper limbs, the victim is usually quick to inactivate the agent by washing the part with water, whereas in burns of the lower limbs this is usually done later, very often only in hospital.
The mortality rate in this group of chemical burn patients was 4.1% (two patients). One of these had 95% T13SA burns due to sulphuric acid. The other had only 6% T13SA burns, but he had also swallowed acid and the cause of death was severe ulcero-haemorrhagic and necrotic damage to the pharynx, oesophagus, and stomach.
Our treatment of this type of burn follows the usual methods adopted in our centre. Immediate hydrotherapy is necessary to prevent continuation of the chemical's destructive activity. We are very cautious with face burns, in which the early excision method is not very suitable.

RESUME. Cette étude considère une période de cinq ans (1991-1995) pendant laquelle 1548 patients brûlés ont été hospitalisés dans notre clinique, dont 49 (3,2%) atteints de brûlures chimiques (38 mâles/Il femelles; âge moyen, 41,4 ans; limites d'âge minimum et maximum, 14 et 80 ans). La cause la plus commune des brûlures chimiques était l'acide. La plupart des brûlures dues aux agents chimiques se sont produites à la maison (73,5% des cas), causées principalement par des actions criminelles ou la négligence. L'extension moyenne des brûlures variait entre 1 et 95%, avec une prévalence de lésions en moins de 10% de la surface corporelle. Trente-six patients (73,5%) présentaient une perte cutanée d'épaisseur variable ou totale. Les parties du corps les plus intéressées étaient la tête, le visage, et le cou (31,8% des patients), les membres inférieurs (19,6%), et le tronc (17,8%). Le taux de mortalité de cette série de patients atteints de brûlures chimiques était 4, 1 %.

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